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IGF-1 LR3

Long R3 IGF-1

Tier 4 · Preclinical Only
Class
IGF-1 analog
Molecular target
IGF-1 receptor
Sequence / structure
83-aa analog: Arg3 substitution plus 13-aa N-terminal extension
Evidence tier
Tier 4 — Preclinical Only
Category
Growth Hormone Axis
Emergency card
Signs something is wrong

Shakiness, cold sweat, sudden intense hunger, pounding heart, confusion or slurred speech — a blood-sugar crash, which this compound can trigger fast.

What to do now

Take fast sugar immediately — juice, regular (non-diet) soda, or glucose tablets. Do not try to wait it out. Recheck after 15 minutes and repeat if still low.

When it is an emergency

If the person becomes confused, cannot swallow safely, has a seizure, or passes out, call 911 — this can be fatal, and crashes from IGF-1 can be severe and prolonged.

Any injection — every time

Allergic reaction: hives, swelling of the lips, tongue or throat, wheezing or dizziness can escalate to anaphylaxis within minutes — call 911 immediately. Site infection: spreading redness, heat, swelling, pus or fever is not wait-and-see; an abscess or cellulitis can need drainage or IV antibiotics. Unverified product: grey-market vials are frequently mislabelled or contaminated, so a reaction may be to endotoxin or the wrong contents, not the named compound.

This is not permission or instruction to use this compound. It is harm-reduction information for someone who has already decided to, so that a bad reaction is recognised and treated. When in doubt, get help — embarrassment is survivable.

Biology & mechanism

An engineered insulin-like growth factor-1 analog. The Arg3 substitution sharply reduces affinity for IGF binding proteins, and the N-terminal extension further limits sequestration — so far more free peptide reaches the IGF-1 receptor, and potency and duration rise substantially versus native IGF-1. It is a laboratory reagent designed for cell culture, not a therapeutic.

What the research actually shows

Ubiquitous as a cell-culture supplement. There are no controlled human trials. Human use is entirely extrapolated from IGF-1 biology and anecdote.

Regulatory status

Not FDA-approved. Sold as a laboratory reagent. Prohibited in sport (WADA S2).

Safety signals

The most acutely hazardous peptide in this library. IGF-1 receptor agonism produces insulin-like effects — severe hypoglycaemia is a real and rapid risk. IGF-1 signalling is mitogenic, and sustained elevation is epidemiologically associated with certain cancers. Cardiac and renal hypertrophy are documented in animal models.

Clinical trial dosing — what the studies actually used

No human trial has ever established a dose for this compound. Any figure circulating online is extrapolated from animal studies or copied between vendors — it was not validated in people. That absence is the single most important dosing fact on this page. It is sold as a cell-culture reagent; its insulin-like activity makes any human dose acutely dangerous.

Reported from clinical trials or FDA labelling as a matter of record. It is not a recommendation, and for unapproved compounds no dose has been shown safe or effective in humans.

We report study doses, not protocols

Above is what was administered in trials or on FDA labels, reported as fact. We do not convert it into a personal protocol, calculate a dose for your body weight, or tell you what to inject or how to reconstitute it — that decision belongs with a licensed physician. See our editorial policy.

References & further reading

Regulatory status changes. This page reflects our reading of public sources as of July 2026 and should be independently verified before it is relied upon.

Important notice Forge Bioenergy publishes scientific reference information only. Nothing on this site is medical advice, a therapeutic claim, or a recommendation to use any substance in humans. Many peptides described here are not approved by the FDA for any use, and several are approved only for narrow indications under prescription. We do not publish dosing, administration, or usage protocols. Consult a licensed physician before making any medical decision.